Catalytic preparation method of parylene AF4

ABSTRACT

The present invention disclosed a preparation method of parylene AF4, which provides a reactant and a reducing agent with the use of catalyst or exposure to UV light with photo-initiator, to shorten the reaction time as a result of minimized the byproduct(s) formation, and obtain high purity (&gt;99.0%) of parylene AF4 product under high concentrated reaction mixture.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a preparation method of octafluoro-(2,2)-paracyclophane (parylene AF4) and, more particularly, the present invention relates to a catalytic or a photocatalytic preparation method of parylene AF4.

2. Description of Related Art

By using the vacuum pyrolysis chemical vapor deposition (CVD) method, parylene can be made into an extremely thin film which has an excellent uniformity, chemical stability and high transparency. Parylene is widely used in the forms of coating thin film, for application on the electrical isolation of printed circuit board, moisture protection of sensors or medical equipment, insulating layers of electrical unit, various protective films or packing materials, and preventing corrosion of metal coatings.

Recently, due to high melting point (about 450° C.) and low dielectric constant (about 2.2) of the fluorinated parylene polymers, such as poly(tetrafluoro-para-xylene) (parylene HT), with its structure shown in formula (1), compared to the traditional parylene N, parylene C, and parylene D, it has superior anti-UV properties, aging resistance, and thermal stability.

In addition, parylene HT can be coated on various irregular substrates' surface, for example, glass, metal, resin, plastic, ceramic and paper. The products coated with parylene HT usually have excellent anti-corrosion, anti-moisture, and insulation protection performance, with the advantages of ultra-thin, transparent, and pinholes free, parylene HT can be used in electronic units, automotive industries, solar energy industries, and the low dielectric constant films of semiconductor industries. Currently, the coating of parylene HT is prepared via CVD process. During the CVD process, free radical monomers are produced and then polymerized into parylene HT on the surface of the object: the method is different from the other general preparation via liquid coating methods (such as dip-coating, spray-coating, sputter-coating, and plasma-coating). The coating process first includes the vaporization of fluorinated parylene dimer, such as parylene AF4 (formula (2)); then forming fluorinated para-xylene radicals by high-temperature pyrolysis; finally deposited on the coated substrate; and polymerized to poly(tetrafluoro-para-xylene), which is commonly named parylene HT, as shown in formula (1), on the surface of the coated object.

The mechanism of the parylene AF4 polymerized to parylene HT via CVD is shown in formula (3).

Many synthetic methods of parylene AF4 has been published in the literature, which mainly use 1,4-bis(chlorodifluoromethyl)benzene (CFB), shown in formula (4), to react with reducing agent Zinc (Zn) and obtain the parylene AF4. In the previous methods, however, in order to prevent the undesired byproducts formation, the reactions were usually carried out in highly diluted conditions, that is, large amount of solvents are necessary in the synthetic methods, therefore, the purchase and storage of the solvent, the process of feeding and the removal of the solvent or impurities will increase the cost of the preparation, coupled with long reaction time, more byproducts and complication of parylene AF4 purification procedure, those methods are not suitable for mass productions.

Therefore, there is a need for the development of a parylene AF4 (octafluoro-[2,2]-paracyclophane) preparation method characterized by high reactant concentration, short reaction time, low cost, less byproducts, easy purification, good reproducibility and stable yield.

SUMMARY OF THE INVENTION

The present invention provides a preparation method for synthesizing parylene AF4 (octafluoro-[2,2]-paracyclophane) using catalyst or photocatalytic, which can reduce the reaction time and increase the yield of parylene AF4 by high concentrated reaction mixture.

In order to achieve the objective, the preparation method of using catalyst of the present invention includes: (A) providing a reactant, a reducing agent, and a catalyst, wherein the reactant is at least one selected from the group consisting of 1,4-bis(chlorodifluoromethyl)benzene (CFB), 1,4-bis(bromodifluoromethyl)benzene (BFB), and 1,4-bis(iododifluoromethyl)benzene (IFB); the reducing agent is at least one selected from the group consisting of zinc, nickel, lead, aluminum, copper, magnesium and tin; and the catalyst is at least one selected from the group consisting of (1) an alkali metal salt, an alkali metal oxide, an alkali metal peroxide, an alkali metal hydroxide, and an alkali metal amide; (2) an alkali earth metal salt, an alkali earth metal oxide, and an alkali earth metal hydroxide; (3) a transition metal salt, a transition metal oxide, a transition metal hydroxide, and a transition metal salt containing hydrate; (4) an amphoteric element salt, an amphoteric element oxide, an amphoteric element hydroxide, an amphoteric element peroxide, and an amphoteric element salt containing hydrate; (5) a non-metallic element acid, and a non-metallic element oxide; (6) a halogen; (7) a phase transfer catalyst of quaternary ammonium salt, a phase transfer catalyst of quaternary phosphonium salt, and a phase transfer catalyst of crown ether; (B) forming a mixture by adding the reactant, the reducing agent, and the catalyst into an aprotic polar solvent; (C) heating the mixture to obtain the parylene AF4 (octafluoro-[2,2]-paracyclophane).

The other preparation method of photocatalytic reaction of the present invention includes: (A) providing a reactant, and a reducing agent, wherein the reactant is at least one selected from the group consisting of 1,4-bis(chlorodifluoromethyl)benzene, 1,4-bis(bromodifluoromethyl)benzene, and 1,4-bis(iododifluoromethyl)benzene; the reducing agent is at least one selected from the group consisting of zinc, nickel, lead, aluminum, copper, magnesium and tin; (B) forming a mixture by adding the reactant and the reducing agent into an aprotic polar solvent; (C) providing an UV light source and heating the mixture to obtain the parylene AF4 (octafluoro-[2,2]-paracyclophane). Wherein, the step (B) of the above further comprises at least a photoinitiator, which is at least one selected from the group consisting of diazo compounds, peroxides, anthraquinones, phosphine oxides, and ketones.

According to the preparation method of the present invention, the reactant may be single component of CFB, BFB, or IFB; or two-component mixture of CFB and BFB, CFB and IFB, or BFB and IFB; or three-component mixture of CFB, BFB and IFB.

According to the preparation method of the present invention, wherein in step (B), the electrochemical potential of the reducing agent must be of the value between 0.45˜2.5 eV, and the reducing agent is at least one selected from the group consisting of zinc, nickel, lead, aluminum, copper, magnesium and tin, wherein zinc is preferable. The weight ratio of the reducing agent to the reactant is 1:1˜5, wherein 1:1.2˜3.0 is preferable.

In the method according to the present invention, the aprotic polar solvent in step (B) is at least one selected from the group consisting of N,N-dimethylacetamide (DMAC), dimethylsulfoxide (DMSO), dimethylformamide (DMF), tetrahydrofurane (THF), N-methylpyrrolidone (NMP), and acetonitrile (AN), wherein DMAC is preferable. The weight ratio of the reactant to the solvent is 1:1˜30, wherein 1:1.5˜10 is preferable.

The method of using catalyst according to the present invention, wherein the catalyst used in step (B) is at least one selected from the group consisting of (1) an alkali metal salt, an alkali metal oxide, an alkali metal peroxide, an alkali metal hydroxide, an alkali metal amide; (2) an alkali earth metal salt, an alkali earth metal oxide, an alkali earth metal hydroxide; (3) a transition metal salt, a transition metal oxide, a transition metal hydroxide, a transition metal salt containing hydrate; (4) an amphoteric element salt, an amphoteric element oxide, an amphoteric element hydroxide, an amphoteric element peroxide, an amphoteric element salt containing hydrate; (5) a non-metallic element acid, a non-metallic element oxide; (6) a halogen; (7) a phase transfer catalyst of quaternary ammonium salt, a phase transfer catalyst of quaternary phosphonium salt, and a phase transfer catalyst of crown ether; wherein (1) the alkali metal salt are preferred to be alkali metal halide salt, alkali metal sulfate, alkali metal carbonate, alkali metal acetate, alkali metal nitrate, alkali metal amine salt, alkali metal organic salt, alkali metal phosphite, alkali metal persulfate, and alkali metal oxalate, wherein CF₃COOLi, LiNH₂, KH₂PO₃, KF, KCl, KBr, KI, CH₃COOK, K₂SO₄, potassium hydrogen phthalate (KHP), potassium tert-butoxide, Na₂SO₄, K₂S₂O₈, K₂CO₃, potassium acrylate, NaCl, NaI, Na₂CO₃, NaNH₂, CH₃COONa, C₂H₅ONa, C₆H₅COONa, CH₃ONa, C₆H₄(OH)COONa, sodium oxalate, and CsF are more preferable, wherein CF₃COOLi, LiNH₂, KH₂PO₃, KF, KCl, KBr, K₁, K₂SO₄, K₂S₂O₈, potassium acrylate, NaCl, NaI, Na₂SO₄, NaNH₂, CH₃COONa, CH₃ONa, sodium oxalate, and Na₂CO₃ are most preferable; the alkali metal oxide is preferred to be Na₂O; and the alkali metal peroxide is preferred to be Na₂O₂; the alkali metal hydroxide are preferred to be LiOH, and NaOH; wherein NaOH is more preferable; the alkali metal amide is preferred to be potassium phthalimide; (2) the alkali earth metal salt are preferred to be alkali earth metal halide salt, alkali earth metal sulfate, alkali earth metal carbonate, and alkali earth metal nitrate, wherein CaCl₂, CaCO₃, CaSO₄, MgCl₂, MgSO₄, MgCO₃, Ba(NO₃)₂ and BaCl₂ are more preferable, wherein CaCl₂, CaCO₃, MgCl₂, MgSO₄, MgCO₃, and BaCl₂ are most preferable; the alkali earth metal oxide are preferred to be MgO and CaO; the alkali earth metal hydroxide is preferred to be Ca(OH)₂; (3) the transition metal salt are preferred to be transition metal halide salt, transition metal acetate, transition metal sulfate, transition metal nitrate, and transition metal carbonate, wherein Ag₂SO₄, NiCl₂, NiCO₃, CuI₂, ZnSO₄, and ZnCl₂ are more preferable, wherein CuI₂ is most preferable; the transition metal oxide is preferred to be ZnO; the transition metal salt containing hydrate are preferred to be Zn(NO₃)₂.6H₂O, Zn(CH₃COO)₂.2H₂O, Fe(NO₃)₃.9H₂O, FeCl₃.6H₂O, MnSO₄.H₂O, CuCl₂.2H₂O, Cu(NO₃)₂.2.5H₂O, and CoCl₂.6H₂O, wherein Zn(NO₃)₂.6H₂O, MnSO₄.H₂O, and Cu(NO₃)₂.2.5H₂O are more preferable; (4) the amphoteric element salt are preferred to be amphoteric element halide salt, amphoteric element sulfate, and amphoteric element nitrate, wherein PbCl₂, Pb(NO₃)₂, and SnCl₂ are more preferable; the amphoteric element oxide are preferred to be PbO and Pb₃O₄; the amphoteric element hydroxide is preferred to be Al(OH)₃; the amphoteric element salt containing hydrate are preferred to be Pb(CH₃COO)₂.3H₂O and Al(NO₃)₃.9H₂O, wherein Pb(CH₃COO)₂.3H₂O is more preferable; (5) the non-metallic element acid is preferred to be boric acid; the non-metallic element oxide is preferred to be P₂O₅; (6) the halogen are preferred to be bromine (Br₂) and iodine (I₂); (7) the phase transfer catalyst of quaternary ammonium salt are preferred to be tetramethyl ammonium chloride (PTC-A₁), phenyl trimethyl ammonium chloride (PTC-A₂), and benzyl triethyl ammonium chloride (PTC-A₃), wherein PTC-A₁ and PTC-A₂ are more preferable; the phase transfer catalyst of quaternary phosphonium salt are preferred to be tetraphenyl phosphonium bromide (PTC-B₁) and methyl triphenyl phosphonium bromide (PTC-B₂), wherein PTC-B₁ is more preferable; and the phase transfer catalyst of crown ether are preferred to be 18-crown-6-ether, 12-crown-4-ether, and 15-crown-5-ether, wherein 18-crown-6-ether is more preferable. The weight ratio of catalyst to reactant is 1:10˜500. In order to shorten the reaction time, the dimerization can be accelerated by adding catalyst and also decreasing the undesired byproducts formation.

The method according to the present invention, wherein in step (C), the reaction temperature is 50˜250° C., 80˜200° C. is preferred, and 100˜135° C. is more preferable.

The method of using catalyst according to the present invention, wherein in step (C), the reaction time is 1˜24 hour, and 1˜12 hour is preferable.

In the method of photocatalytic reaction according to the present invention, step (B) further comprises a photo-initiator, and the photo-initiator is at least one selected from the group consisting of diazo compounds such as azobisisobutyronitrile (AIBN); peroxides such as benzoyl peroxide (BPO); anthraquinones such as 2-ethylanthraquinone (EAQ); phosphine oxides such as diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (DTBPO); and ketones such as 1-hydroxy-cyclohexyl phenyl ketone (HCPK), 2-hydroxy-2-methyl-1-phenyl-1-propanone (HMPP), benzyl-α,α-dimethyl ketal (BDK) and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one (MPMPO), wherein the weight ratio of the photo-initiator to the reactant is 1:10˜100, and 1:30˜60 is more preferable.

The method of preparing parylene AF4 of the present invention, by adding at least a reactant selected from the group of CFB, BFB, and IFB into a small amount of solvent combined with a reducing agent to form a highly concentrated reaction mixture, catalyzed by adding catalyst or photocatalytic reaction with photo-initiator, and accelerated the reaction by heating to obtain parylene AF4. The capacity of parylene AF4 production is significantly increased by the high concentrated reaction mixture, therefore, the large scale of parylene AF4 manufacture promises great commercial advantages.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Embodiment 1

This embodiment involves providing a 250 ml three-necked bottle and purging with nitrogen, then adding 75 ml of DMAC solvent, 15.68 g (0.24 mol) of reducing agent zinc powder, and 0.21 g (3.5 mmol) of catalyst KF, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CH₃ is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 135° C., the feeding time is about 2 hours and the reaction is continued for 3 hours. The crude product is filtered and washed by DMAC. The double bond-containing byproduct in filtrate is oxidized by potassium permanganate, and the filtrate is concentrated and water is added to the resulting crude solid in order to remove the inorganic substances. The crude solid obtained from filtration and recrystallized in chloroform (CHCl₃) to obtain 8.43 g of pure parylene AF4 (purity 99.5%, yield 40.28%). The parylene AF4 product is confirmed by analysis: the molecular weight of 352.0 g/mol is confirmed by GC/MS analysis, H¹NMR is δ 7.1 ppm (s), and F¹⁹ NMR is δ −118.0 ppm (s).

Embodiment 2

In this embodiment of the present invention, a 250 ml three-necked bottle is provided and purged with nitrogen, then 50 ml of DMAC solvent is added, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (0.6 mmol) of catalyst stirred and preheated to 120° C. Then the mixture of 14.82 g (0.06 mol) of reactant CFB and 1.95 g (0.006 mol) of reactant BFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 140° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 3.58 g of parylene AF4 is obtained (purity 99.63%, yield 31.0%).

Embodiment 3

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 150 ml of DMSO solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (0.6 mmol) of catalyst KI, stirred and preheated to 120° C. Then 14.82 g (0.06 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 131° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.34% of purity and 26.7% of yield.

Embodiment 4

Provide a 1000 ml three-necked bottle and purge with nitrogen, then add 300 ml of DMAC solvent, 125.4 g (1.92 mot) of reducing agent zinc powder, and 1.9 g (11.4 mmol) of catalyst KI, stirred and preheated to 120° C. Then 237.0 g (0.96 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 142° C., the feeding time is about 3 hours and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 77.2 g of parylene AF4 is obtained (purity 99.7%, yield 45.7%).

Embodiment 5

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mol) of reducing agent zinc powder, and 0.2 g (3.4 mmol) of catalyst NaCl, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 135° C., the feeding time is about 2 hours and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 7.9 g of parylene AF4 is obtained (purity 99.52%, yield 37.44%).

Embodiment 6

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mot) of reducing agent zinc powder, and 0.2 g (1.4 mmol) of catalyst sodium sulfate (Na₂SO₄), stirred and preheated to 120° C. Then 29.64 g (0.12 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 134° C., the feeding time is about 2 hours and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 7.74 g of parylene AF4 is obtained (purity 99.66%, yield 36.7%).

Embodiment 7

This embodiment involves to providing a 250 ml three-necked bottle and purging with nitrogen, then adding 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.63 g (15.8 mmol) of catalyst sodium hydroxide (NaOH), stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 130° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 3.7 g of parylene AF4 is obtained (purity 99.28%, yield 35.24%).

Embodiment 8

A 250 ml three-necked bottle is provided and purged with nitrogen, then added with 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (2.5 mmol) of catalyst MgO, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 130° C., the feeding time is about 1 hour and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.39% of purity and 30.10% of yield.

Embodiment 9

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mot) of reducing agent zinc powder, and 0.20 g (1.8 mmol) of catalyst CaCl₂, stirred and preheated to 120° C. Then 29.64 g (0.12 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 132° C., the feeding time is about 2 hours and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 8.36 g of parylene AF4 is obtained (purity 99.45%, yield 39.81%).

Embodiment 10

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (0.59 mmol) of catalyst MnSO₄.1H₂O, stirred and preheated to 120° C. Then 14.82 g (0.06 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 140° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.59% of purity and 31.43% of yield.

Embodiment 11

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (0.32 mmol) of catalyst CuI₂, stirred and preheated to 120° C. Then 14.82 g (0.06 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 140° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.37% of purity and 30.6% of yield.

Embodiment 12

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.20 g (2.5 mmol) of catalyst ZnO, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 132° C., the feeding time is about 1 hour and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.6% of purity and 31.00% of yield.

Embodiment 13

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (1.3 mmol) of catalyst Al(OH)₃, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 136° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.5% of purity and 31.42% of yield.

Embodiment 14

This embodiment of the present invention provides a 250 ml three-necked bottle and is purged with nitrogen, then adding 75 ml of DMAC solvent, 15.68 g (0.24 mol) of reducing agent zinc powder, and 0.28 g (1.0 mmol) of catalyst PbCl₂, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 130° C., the feeding time is about 2 hours and the reaction is continued for 2 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 7.6 g of parylene AF4 is obtained with 99.46% of purity and 36.2% of yield.

Embodiment 15

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mol) of reducing agent zinc powder, and 0.20 g (0.53 mmol) of catalyst Pb(CH₃COO)₂.3H₂O, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 134° C., the feeding time is about 2 hours and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 6.63 g of parylene AF4 is obtained with 99.3% of purity and 31.4% of yield.

Embodiment 16

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mot) of reducing agent zinc powder, and 0.30 g (2.7 mmol) of catalyst PTC-A₁, stirred and preheated to 120° C. Then 29.64 g (0.12 mot) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 136° C., the feeding time is about 2 hours and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 8.6 g of parylene AF4 is obtained with 99.45% of purity and 40.76% of yield.

Embodiment 17

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mot) of reducing agent zinc powder, and 0.50 g (1.4 mmol) of catalyst PTC-B₂, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 140° C., the feeding time is about 2 hours and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 7.53 g of parylene AF4 is obtained with 99.61% of purity and 35.7% of yield.

Embodiment 18

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 75 ml of DMAC solvent, 15.68 g (0.24 mol) of reducing agent zinc powder, and 0.40 g (1.5 mmol) of catalyst 18-crown-6, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature gradually increased to 136° C., the feeding time is about 2 hours and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 8.04 g of parylene AF4 is obtained with 99.72% of purity and 38.1% of yield.

Embodiment 19

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.30 g (13 mmol) of catalyst LiNH₂, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 136° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.41% of purity and 40.5% of yield.

Embodiment 20

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.30 g (12.5 mmol) of catalyst LiOH, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 136° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.52% of purity and 29.8% of yield.

Embodiments 21˜100

The preparation methods, reactants, reducing agents, catalysts, solvents and the dosages, reaction temperature, reaction time and the yields of parylene AF4 of embodiments 21˜100 are shown in table 1.

Embodiment 101

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent and 7.84 g (0.12 mol) of reducing agent zinc powder, and exposed to UV light, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CH₃ is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 134° C., the feeding time is about 1 hour and the reaction is continued for 20 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.23% of purity and 33.9% of yield.

Embodiment 102

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.30 g (1.83 mmol) of photo-initiator AIBN and then exposed to UV light, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 132° C., the feeding time is about 1 hour and the reaction is continued fir 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.31% of purity and 33.3% of yield.

Embodiments 103˜115

The preparation methods of embodiments 103˜115 are the same as embodiment 102, and their reactants, reducing agents, photo-initiators, solvents and the dosages, reaction temperature, reaction time and the yields of parylene AF4 of embodiments 103˜115 are shown in table 2.

Comparative Example 1

Provide a 250 nil three-necked bottle and purge with nitrogen, then add 100 ml of DMAC solvent, and 31.36 g (0.48 mol) of reducing agent zinc powder, stirred and preheated to 120° C. Then 59.28 g (0.24 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 130° C., the feeding time is about 2 hours and the reaction is continued for 26 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 14.50 g of parylene AF4 is obtained with 99.33% of purity and 34.5% of yield.

Comparative Example 2

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 50 ml of DMAC solvent, 3.24 g (0.12 mol) of reducing agent aluminum powder, and 0.10 g (0.6 mmol) of catalyst KI, stirred and preheated to 120° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 138° C., the feeding time is about 1 hour and the reaction is continued for 3 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.45% of purity and 11.8% of yield.

Comparative Example 3

A 250 ml three-necked bottle is provided and purged with nitrogen, there adding 150 ml of AN solvent, 7.84 g (0.12 mol) of reducing agent zinc powder, and 0.10 g (0.6 mmol) of catalyst KI, stirred and preheated to 80° C. Then 14.82 g (0.06 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 82.5° C., the feeding time is about 1 hour and the reaction is continued for 20 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and 1.06 g of parylene AF4 is obtained with 99.64% of purity and 10.05% of yield.

Comparative Example 4

Provide a 250 ml three-necked bottle and purge with nitrogen, then add 100 ml of DMAC solvent, and 15.68 g (0.24 mol) of reducing agent Zinc powder, and exposed to UV light, stirred and preheated to 120° C. Then 29.64 g (0.12 mol) of reactant CFB is added dropwise to the reaction bottle, and the reaction temperature is gradually increased to 130° C., the feeding time is about 2 hour and the reaction is continued for 20 hours. The crude product is purified and analyzed by the same methods of embodiment 1 and parylene AF4 is obtained with 99.68% of purity and 35.7% of yield.

TABLE 1 The parylene AF4 preparation enhanced by catalyst.

Reaction Parylene Reducing Solvent temperature Reaction AF4 Reactant (R) agent (RA) Catalyst (X) (S) (° C.) time (hr) yield Embodiment (g/mol) (g/mol) (g/mmol) (ml) Initial/End Feed/End (%) 1 CFB Zn KF DMAC 120/135 2/3 40.28 29.64/0.12 15.68/0.24 0.21/3.5 75 2 CFB Zn KI DMAC 120/140 1/3 31.0 14.82/0.06 7.84/0.12 0.1/0.6 50 BFB 1.95/0.006 3 CFB Zn KI DMAC 120/131 1/3 26.7 14.82/0.06 7.84/0.12 0.1/0.6 150 4 CFB Zn KI DMAC 120/142 3/3 45.7 237.0/0.96 125.4/1.92 1.9/11.4 300 5 CFB Zn NaCl DMAC 120/135 2/2 37.44 29.64/0.12 15.68/0.24 0.2/3.4 75 6 CFB Zn Na₂SO₄ DMAC 120/134 2/2 36.7 29.64/0.12 15.68/0.24 0.2/1.4 75 7 CFB Zn NaOH DMAC 120/130 1/3 35.24 14.82/0.06 7.84/0.12 0.63/15.8 50 8 CFB Zn MgO DMAC 120/130 1/2 30.1 14.82/0.06 7.84/0.12 0.1/2.5 50 9 CFB Zn CaCl₂ DMAC 120/132 2/2 39.81 29.64/0.12 15.68/0.24 0.2/1.8 75 10 CFB Zn MnSO₄•1H₂O DMAC 120/140 1/3 31.43 14.82/0.06 7.84/0.12 0.1/0.59 50 11 CFB Zn CuI₂ DMAC 120/140 1/3 30.6 14.82/0.06 7.84/0.12 0.1/0.32 50 12 CFB Zn ZnO DMAC 120/132 1/2 31.0 14.82/0.06 7.84/0.12 0.2/2.5 50 13 CFB Zn Al(OH)₃ DMAC 120/136 1/3 31.42 14.82/0.06 7.84/0.12 0.1/1.3 50 14 CFB Zn PbCl₂ DMAC 120/130 2/2 36.2 29.64/0.12 15.68/0.24 0.28/1.0 75 15 CFB Zn Pb(CH₃COO)₂•3H₂O DMAC 120/134 2/3 31.4 29.64/0.12 15.68/0.24 0.2/0.53 75 16 CFB Zn PTC-A₁ DMAC 120/136 2/3 40.76 29.64/0.12 15.68/0.24 0.3/2.7 75 17 CFB Zn PTC-B₂ DMAC 120/140 2/3 35.7 29.64/0.12 15.68/0.24 0.5/1.4 75 18 CFB Zn 18-crown-6 DMAC 120/136 2/3 38.1 29.64/0.12 15.68/0.24 0.4/1.5 75 19 CFB Zn LiNH₂ DMAC 120/136 1/3 40.5 14.82/0.06 7.84/0.12 0.3/13 50 20 CFB Zn LiOH DMAC 120/136 1/3 29.8 14.82/0.06 7.84/0.12 0.3/12.5 50 21 CFB Zn CF₃CO₂Li DMAC 120/136 1/3 33.7 14.82/0.06 7.84/0.12 0.3/2.5 50 22 CFB Zn KF DMAC 120/132 2/2 37.91 29.64/0.12 15.68/0.24 0.3/5.2 75 23 BFB Zn KF DMAC 120/136 1/2 31.0 20.16/0.06 7.84/0.12 0.1/1.7 50 24 CFB Zn KF DMAC 120/140 1/3 24.5 14.82/0.06 7.84/0.12 0.1/1.7 50 BFB 1.95/0.006 25 CFB Zn KF DMAC  60/140 1/3 27.0 14.82/0.06 7.84/0.12 0.1/1.7 50 26 CFB Zn KCl DMAC 120/135 2/2 33.18 29.64/0.12 15.68/0.24 0.2/2.7 75 27 CFB Zn KBr DMAC 120/132 2/2 35.55 29.64/0.12 15.68/0.24 0.2/1.7 75 28 CFB Zn KI DMAC 120/126 2/2 32.7 29.64/0.12 15.68/0.24 0.5/3.0 75 29 BFB Zn KI DMAC 120/136 1/2 32.0 20.16/0.06 7.84/0.12 0.1/0.6 50 30 CFB Zn KI DMAC 120/131 1/3 23.8 14.82/0.06 7.84/0.12 0.1/0.6 150 31 CFB Zn KI DMAC  60/140 1/3 30.5 14.82/0.06 7.84/0.12 0.1/0.6 50 32 CFB Zn KI DMAC  80/100 1/5 26.7 14.82/0.06 7.84/0.12 0.1/0.6 50 33 CFB Zn KI DMAC 100/120 1/5 29.2 14.82/0.06 7.84/0.12 0.1/0.6 50 34 CFB Zn K₂CO₃ DMAC 120/134 2/2 29.5 29.64/0.12 15.68/0.24 0.2/1.45 75 35 CFB Zn K₂PO₄ DMAC 120/134 2/2 32.6 29.64/0.12 15.68/0.24 0.2/1.15 75 36 CFB Zn KH₂PO₃ DMAC 120/140 1/2 36.2 14.82/0.06 7.84/0.12 0.1/0.83 50 37 CFB Zn K₂S₂O₈ DMAC 120/136 2/3 33.3 29.64/0.12 15.68/0.24 0.2/0.74 75 38 CFB Zn CH₃COOK DMAC 120/135 1/3 28.1 14.82/0.06 7.84/0.12 0.3/3.1 50 39 CFB Zn KHP DMAC 120/136 1/3 27.9 14.82/0.06 7.84/0.12 0.1/0.5 50 40 CFB Zn NaCl DMAC 120/138 2/1 34.12 29.64/0.12 15.68/0.24 0.5/8.5 75 41 CFB Zn NaI DMAC 120/135 2/2 35.55 29.64/0.12 15.68/0.24 0.2/1.3 75 42 CFB Zn Na₂CO₃ DMAC 120/134 2/2 35.7 29.64/0.12 15.68/0.24 0.2/1.9 75 43 CFB Zn Na₂O DMAC 120/135 1/3 32.4 14.82/0.06 7.84/0.12 0.1/1.6 50 44 CFB Zn Na₂O₂ DMAC 120/136 1/3 37.3 14.82/0.06 7.84/0.12 0.3/3.85 50 45 CFB Zn C₂H₅ONa DMAC 120/136 1/3 25.8 14.82/0.06 7.84/0.12 0.3/4.4 50 46 CFB Zn CH₃COONa DMAC 120/135 1/3 33.3 14.82/0.06 7.84/0.12 0.3/3.66 50 47 CFB Zn C₆H₅COONa DMAC 120/136 1/3 29.5 14.82/0.06 7.84/0.12 0.3/2.1 50 48 CFB Zn CH₃ONa DMAC 120/136 1/3 33.8 14.82/0.06 7.84/0.12 0.3/5.6 50 49 CFB Zn CsF DMAC 120/140 1/2 29.52 14.82/0.06 7.84/0.12 0.1/0.66 50 50 CFB Zn MgCl₂ DMAC 120/130 2/2 31.9 29.64/0.12 15.68/0.24 0.2/2.1 75 51 CFB Zn MgSO₄ DMAC 120/132 2/2 38.39 29.64/0.12 15.68/0.24 0.2/1.7 75 52 CFB Zn MgCO₃ DMAC 120/132 1/2 33.8 14.82/0.06 7.84/0.12 0.1/0.2 50 53 BFB Zn CaCl₂ DMAC 120/136 1/2 32.8 20.16/0.06 7.84/0.12 0.1/0.9 50 54 CFB Zn CaCl₂ DMAC 120/140 1/3 31.4 14.82/0.06 7.84/0.12 0.1/0.9 50 BFB 1.95/0.006 55 CFB Zn CaCl₂ DMAC  60/140 1/3 28.4 14.82/0.06 7.84/0.12 0.1/0.9 50 56 CFB Zn CaCO₃ DMAC 120/134 2/2 32.85 29.64/0.12 15.68/0.24 0.2/2.0 75 57 CFB Zn CaSO₄ DMAC 120/132 1/2 29.5 14.82/0.06 7.84/0.12 0.1/0.74 50 58 CFB Zn CaO DMAC 120/140 1/3 35.24 14.82/0.06 7.84/0.12 0.1/1.8 50 59 CFB Zn Ca(OH)₂ DMAC 120/130 1/2 23.14 14.82/0.06 7.84/0.12 0.3/4.0 50 60 CFB Zn Ba(NO₃)₂ DMAC 120/136 1/3 29.52 14.82/0.06 7.84/0.12 0.1/0.38 50 61 CFB Zn BaCl₂ DMAC 120/140 1/2 34.28 14.82/0.06 7.84/0.12 0.1/0.48 50 62 CFB Zn FeCl₃•6H₂O DMAC 120/136 1/3 25.3 14.82/0.06 7.84/0.12 0.1/0.37 50 63 CFB Zn Fe(NO₃)₃•9H₂O DMAC 120/136 1/2 20.0 14.82/0.06 7.84/0.12 0.1/0.25 50 64 CFB Zn CoCl₂•6H₂O DMAC 120/140 1/2 28.6 14.82/0.06 7.84/0.12 0.1/0.42 50 65 CFB Zn Co(NO₃)₂•6H₂O DMAC 120/140 1/3 17.8 14.82/0.06 7.84/0.12 0.1/0.344 50 66 CFB Zn NiCl₂ DMAC 120/140 1/3 10.86 14.82/0.06 7.84/0.12 0.1/0.77 50 67 CFB Zn Ni(CH₃COO)₂•4H₂O DMAC 120/140 2/3 18.1 29.64/0.12 15.68/0.24 0.2/0.8 75 68 CFB Zn NiCO₃ DMAC 120/140 1/2 26.7 14.82/0.06 7.84/0.12 0.1/0.84 50 69 CFB Zn Ni—Al—Si DMAC 120/140 1/2 36.6 14.82/0.06 7.84/0.12 0.5/ 50 70 CFB Zn Ni(NO₃)₂•6H₂O DMAC 120/140 1/3 13.8 14.82/0.06 7.84/0.12 0.1/0.34 50 71 CFB Zn CuCl₂•2H₂O DMAC 120/140 1/3 24.5 14.82/0.06 7.84/0.12 0.1/0.59 50 72 CFB Zn CuSO₄•5H₂O DMAC 120/134 1/2 15.8 14.82/0.06 7.84/0.12 0.1/0.4 50 73 CFB Zn Cu(NO₃)₂•2.5H₂O DMAC 120/140 1/3 30.96 14.82/0.06 7.84/0.12 0.1/0.43 50 74 CFB Zn ZnCl₂ DMAC 120/134 1/2 25.7 14.82/0.06 7.84/0.12 0.5/3.7 50 75 CFB Zn ZnSO₄ DMAC 120/132 1/2 24.8 14.82/0.06 7.84/0.12 0.2/1.24 50 76 CFB Zn Zn(NO₃)₂•6H₂O DMAC 120/132 1/2 30.8 14.82/0.06 7.84/0.12 0.2/0.68 50 77 CFB Zn Zn(CH₃COO)₂•2H₂O DMAC 120/136 1/3 25.7 14.82/0.06 7.84/0.12 0.1/0.46 50 78 CFB Zn Ag₂SO₄ DMAC 120/134 1/2 23.8 14.82/0.06 7.84/0.12 0.1/0.32 50 79 CFB Zn Al(NO₃)₃•9H₂O DMAC 120/140 1/2 22.3 14.82/0.06 7.84/0.12 0.2/0.53 50 80 CFB Zn SnCl₂ DMAC 120/140 2/3 20.5 29.64/0.12 15.68/0.24 0.2/0.1 75 81 CFB Zn Pb(NO₃)₂ DMAC 120/130 2/2 26.2 29.64/0.12 15.68/0.24 0.33/1.0 75 82 CFB Zn PbO DMAC 120/140 2/2 38.1 29.64/0.12 15.68/0.24 0.2/0.9 75 83 CFB Zn Pb₃O₄ DMAC 120/136 1/2 32.1 14.82/0.06 7.84/0.12 0.1/0.15 50 84 CFB Zn (NH₄)₂SiF₆ DMAC 120/140 1/3 33.6 14.82/0.06 7.84/0.12 0.1/0.56 50 85 CFB Zn P₂O₅ DMAC 120/140 1/2 33.5 14.82/0.06 7.84/0.12 0.1/0.66 50 86 CFB Zn H₃BO₃ DMAC 120/130 1/3 32.4 14.82/0.06 7.84/0.12 0.1/1.6 50 87 CFB Zn PTC-A₂ DMAC 120/140 2/3 35.7 29.64/0.12 15.68/0.24 0.43/2.5 75 88 CFB Zn PTC-A₃ DMAC 120/134 2/2 23.8 29.64/0.12 15.68/0.24 0.3/1.4 75 89 CFB Zn PTC-B₁ DMAC 120/135 2/3 37.91 29.64/0.12 15.68/0.24 0.5/1.2 75 90 CFB Zn 12-crown-4 DMAC 120/140 1/3 32.4 14.82/0.06 7.84/0.12 0.3/1.7 50 91 CFB Zn 15-crown-5 DMAC 120/140 1/3 35.2 14.82/0.06 7.84/0.12 0.3/1.36 50 92 CFB Zn NaNH₂ DMAC 120/135 1/3 32.95 14.82/0.06 7.84/0.12 0.3/7.7 50 93 CFB Zn C₆H₄(OH)COONa DMAC 120/135 1/3 27.6 14.82/0.06 7.84/0.12 0.3/1.9 50 94 CFB Zn C₄H₉KO DMAC 120/135 1/3 28.6 14.82/0.06 7.84/0.12 0.3/2.7 50 95 CFB Zn C₃H₃KO₂ DMAC 120/137 1/3 31.6 14.82/0.06 7.84/0.12 0.3/2.7 50 96 CFB Zn C₂Na₂O₄ DMAC 120/137 1/3 32.67 14.82/0.06 7.84/0.12 0.3/2.24 50 97 CFB Zn C₈H₄KNO₂ DMAC 120/137 1/3 27.9 14.82/0.06 7.84/0.12 0.3/1.62 50 98 CFB Zn I₂ DMAC 120/136 1/3 31.7 14.82/0.06 7.84/0.12 0.3/1.62 50 99 CFB Zn Br₂ DMAC 120/134 1/3 37.0 14.82/0.06 7.84/0.12 0.3/1.18 50 100 CFB Zn HCl (36%) DMAC 120/134 1/3 18.67 14.82/0.06 7.84/0.12 0.3/1.88 50 Comparative CFB Zn none DMAC 120/130  2/26 34.5 example 1 59.28/0.24 31.36/0.48 100 Comparative CFB Zn KI DMAC 120/138 1/3 11.8 example 2 14.82/0.06 3.24/0.12 0.1/0.6 50 Comparative CFB Zn KI AN   80/82.5  1/20 10.05 example 3 14.82/0.06 7.84/0.12 0.1/0.6 150 Note: some abbreviation chemical name is as follows PTC-A₁ Tetramethyl ammonium chloride PTC-A₂ Phenyl trimethyl ammonium chloride PTC-A₃ Benzyl triethyl ammonium hydroxide PTC-B₁ Tetraphenylphosphonium bromide PTC-B₂ Methyl triphenylphosphonium bromide KHP Potassium hydrogen phthalate CFB 1,4-bis(chlorodifluoromethyl)Benzene BFB 1,4-bis(bromodifluoromethyl)Benzene DMAC N,N-Dimethylacetamide DMF N,N-Dimethylformamide DMSO Dimethylsulfoxide AN Acetonitrile C₄H₉KO Potassium tert-butoxide C₃H₃KO₂ Potassium acrylate C₂Na₂O₄ Sodium oxalate C₈H₄KNO₂ Potassium phthalimide K₂S₂O₈ Potassium persulfate Ni—Al—Si Nickel-Nickel Oxide deposited on silica-Alumina XERTEX Dohrmann (German company) product for GC packing column usage

TABLE 2 The parylene AF4 preparation accelerated by UV with photo-initiator

Reaction parylene Reactant Reducing Solvent temperature Reaction AF4 (R) agent (RA) UV & initiator (P) (S) (° C.) time (hr) yield Embodiment (g/mol) (g/mol) (g/mmol) (ml) Initial/End Feed/End (%) 101 CFB Zn UV DMAC 120/134  1/20 33.9 14.82/0.06 7.84/0.12 50 102 CFB Zn UV + AIBN DMAC 120/132 1/3 33.3 14.82/0.06 7.84/0.12 0.3/1.83 50 103 CFB Zn UV + HMPP DMAC 120/136 1/7 37.7 14.82/0.06 7.84/0.12 0.3/1.83 50 104 CFB Zn UV + HCPK DMAC 120/135 1/5 32.4 14.82/0.06 7.84/0.12 0.3/1.47 50 105 CFB Zn UV + BDK DMAC 120/140 1/4 29.5 14.82/0.06 7.84/0.12 0.3/1.17 50 106 CFB Zn UV + BPO DMAC 120/140 1/4 27.7 14.82/0.06 7.84/0.12 0.3/1.24 50 107 CFB Zn UV + DTBPO DMAC 120/136 1/4 24.8 14.82/0.06 7.84/0.12 0.3/0.86 50 108 CFB Zn UV + MPMPO DMAC 120/136 1/4 36.2 14.82/0.06 7.84/0.12 0.3/1.07 50 109 CFB Zn UV + EAQ DMAC 120/138 1/4 36.6 14.82/0.06 7.84/0.12 03/1.27 50 110 CFB Zn UV + HMPP DMAC 120/136 1/3 36.5 20.16/0.06 7.84/0.12 0.3/1.83 50 111 CFB Zn UV + HMPP DMAC 120/136 1/4 25.7 14.82/0.06 7.84/0.12 0.3/1.83 50 112 CFB Zn UV + HMPP DMAC  60/133 1/3 29.1 14.82/0.06 7.84/0.12 0.3/1.83 50 113 CFB Zn UV + HMPP DMAC 120/136 1/3 27.6 14.82/0.06 7.84/0.12 0.3/1.83 150 114 CFB Zn UV + HMPP DMAC 120/135 1/2 30.0 14.82/0.06 15.86/0.24 0.3/1.83 50 115 CFB Zn UV + HMPP DMAC 120/134 1/4 30.5 14.82/0.06 7.84/0.12 1.0/6.1 50 Comparative CFB Zn UV DMAC 120/130  2/20 35.7 example 4 29.64/0.12 15.68/0.24 100 Note: The above chemical name is as follows. AIBN 2,2-azobisisobutyronitrile HMPP 2-hydroxy-2-methyl-1-phenyl-1-propanone HCPK 1-hydroxy-cyclohexyl-phenyl ketone BDK benzyl α,α-dimethyl ketal BPO benzoyl peroxide DTBPO diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide EAQ 2-ethylanthraquinone MPMPO 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one

Although the present invention has been explained in relation to its preferred embodiment, it is understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. 

What is claimed is:
 1. A method of preparing parylene AF4 (octafluoro-[2,2]-paracyclophane), which comprises the steps of: (A) providing a reactant, a reducing agent, and a catalyst, wherein: (i) the reactant is at least one selected from the group consisting of 1,4-bis(chlorodifluoromethyl)benzene, 1,4-bis(bromodifluoromethyl)benzene, and 1,4-bis(iododifluoromethyl)benzene; (ii) the reducing agent is at least one selected from the group consisting of zinc, nickel, lead, aluminum, copper, magnesium and tin; and (iii) the catalyst is at least one selected from the group consisting of an alkali metal salt, an alkali metal oxide, an alkali metal peroxide, an alkali metal hydroxide, and an alkali metal amide, wherein the alkali metal salt is at least one selected from the consisting of alkali metal halide salt alkali metal sulfate, alkali metal carbonate, alkali metal acetate, alkali metal nitrate, alkali metal amine salt, alkali metal organic salt, alkali metal phosphite, alkali metal persulfate, and alkali metal oxalate; and the alkali metal halide salt is at least one selected from the group consisting of KCl, KBr, KI, NaCl, and NaI; (B) forming a mixture by adding the reactant, the reducing agent, and the catalyst into an aprotic polar solvent, wherein the weight ratio of the reactant to the solvent is 1:1.5-10; and (C) heating the mixture to obtain the parylene AF4.
 2. The method according to claim 1, wherein the aprotic polar solvent in step (B) is at least one selected from the group consisting of N,N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, tetrahydrofurane, N-methylpyrrolidone, and acetonitrile.
 3. The method according to claim 1, in step (B), wherein the weight ratio of the reducing agent to the reactant is 1:1˜5.
 4. The method according to claim 1, in step (B), wherein the weight ratio of the catalyst to the reactant is 1:10˜500.
 5. The method according to claim 1, in step (C), wherein the reacting temperature is 50˜250° C.
 6. The method according to claim 1, wherein the catalyst comprises an alkali metal salt selected from the group consisting of alkali metal halide salt, alkali metal sulfate, alkali metal carbonate, alkali metal acetate, alkali metal nitrate, alkali metal amine salt, alkali metal organic salt, alkali metal phosphite, alkali metal persulfate, alkali metal oxalate, and combinations thereof; and the alkali metal halide salt is at least one selected from the group consisting of KCl, KBr, KI, NaCl, and NaI.
 7. The method according to claim 1, wherein the catalyst comprises an alkali metal oxide.
 8. The method according to claim 1, wherein the catalyst comprises an alkali metal peroxide.
 9. The method according to claim 1, wherein the catalyst comprises an alkali metal hydroxide.
 10. The method according to claim 1, wherein the catalyst comprises an alkali metal amide.
 11. The method according to claim 6, wherein the catalyst comprises an alkali metal halide salt selected from the group consisting of KCl, KBr, KI, NaCl, NaI, and combinations thereof. 